Paper feed tractor

Abstract

A paper feed tractor comprising a tractor frame including a pair of side frames and a belt guide disposed between and coupled to the side frames, a sprocket wheel supported for rotation between the two side frames, an endless belt adapted to be driven by the sprocket wheel to slidably travel on guide walls formed on three peripheral faces of the belt guide, and a cover mounted at a side thereof for pivotal motion on one of the side frames from and to a position in which it extends on a linear one of the guide walls of the belt guide. The endless belt has feed pins provided projectingly in a row at equal intervals on an outer peripheral face thereof, and a paper holder provided on the cover is positioned, on at least one side of the feed pins, in parallel to the outer peripheral face of the endless belt. The outer peripheral face of the endless belt has a non-slipping face formed thereon on which concave and convex portions of a small difference in dimension are formed to reduce a possible slip between the outer peripheral face of the endless belt and paper transported by the endless belt.

What is claimed is: 
     
       1. A paper feed tractor for transporting paper having feed holes formed at equal intervals in a row along a side edge thereof, comprising 
     
     
       a tractor frame, a belt guide formed on said tractor frame, a sprocket wheel supported for rotation on said tractor frame, an endless belt extending between said sprocket wheel and said tractor frame and adapted to be driven by said sprocket wheel to travel along a guide path formed by said sprocket wheel and said belt guide, said endless belt having feed pins provided projectingly on an outer peripheral face thereof in a row at the same equal intervals to those of the feed holes formed along the side edge of the paper, said belt guide having a liner guide portion thereon, a cover supported at a side edge of said tractor frame along said linear guide portion of said belt guide for selective pivotal motion between a first position in which said cover extends substantially in a parallel relationship above said linear guide portion of said belt guide and a second position in which said cover opens a location above said linear guide portion of said belt guide, and a paper holder formed in the form of an elongated planar plate and bent at the longitudinal opposite end portions thereof to support said paper holder on a face of said cover opposing to said linear guide portion of said belt guide such that a main portion of said paper holder is spaced from said face of said cover, wherein said paper holder is disposed such that, when said cover is at the first position, said main portion thereof is opposed to said linear guide portion of said belt guide in parallel to the longitudinal direction of said linear guide portion and is positioned in parallel to said outer peripheral face of said endless belt on at least one side of said feed pins of said endless belt which travels on said linear guide portion of said belt guide, and   a peripheral face portion of said outer peripheral face of said endless belt on which said feed pins are provided projectingly being formed into a non-slipping face on which concave and convex portions of a small difference in dimension are formed wherein when said cover is at the first position, the distance between said convex portions of said non-slipping face of said endless belt and a face of said main portion of said paper holder opposing to said convex portions is made smaller than the thickness of the paper.   
     
     
       2. A paper feed tractor according to claim 1, wherein said main portion of said paper holder has an elongated hole formed therein parallel to the longitudinal direction of said linear guide portion of said belt guide for allowing said feed pins of said endless belt which travels on said liner guide portion of said belt guide to travel in said elongated hole, and said main portion of said paper holder is positioned in parallel to said outer peripheral face of said endless belt.